Grooms walk Derby horses Revolutionary (3) and Mylute (6) to the paddock area before the start of the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/J. David Ake)

Megan Grable, left, from St. Louis, Mo., and Cindy Brenner, of Louisville, Ky., wait under a plastic tarp for the next race during the 139th Kentucky Derby at Churchill Downs Saturday, May 4, 2013, in Louisville, Ky. (AP Photo/David Goldman)